1. Technical Field
Example embodiments of the present invention relate in general to a method of changing an association ID (AID) and more specifically to a method of changing an old AID to a new AID in a wireless local area network (WLAN) system.
2. Related Art
Various wireless communication techniques are being developed along with the recent development of an information communication technology. In particular, wireless local area network (WLAN) is a technology that can provide a wireless connection to the Internet in a limited service area such as a home or office building using portable terminals, for example, a personal digital assistant (PDA), a laptop computer, and a portable multimedia player (PMP) based on a wireless frequency technology.
Standards for WLAN technology is developed and standardized by IEEE 802.11 working group (WG) in the Institute of Electrical and Electronics Engineering (IEEE) 802.11. IEEE 802.11a provides a transfer rate of 54 Mbps using 5 GHz unlicensed band. IEEE 802.11b provides a transfer rate of 11 Mbps by using direct sequence spread spectrum (DSSS) in 2.4 GHz band. IEEE 802.11g provides a transfer rate of 54 Mbps by using orthogonal frequency division multiplexing (OFDM) in 2.4 GHz band. IEEE 802.11n provides a transfer rate of 300 Mbps for two spatial streams by using multiple-input multiple-output OFDM (MIMO-OFDM). IEEE 802.11n supports a channel bandwidth of up to 40 MHz and, in this case, provides a transfer rate of 600 Mbps.
Along with the wide deployment of WLAN and the diversification of applications using WLAN, new WLAN techniques are increasingly needed to support higher throughput than IEEE 802.11n. Very high throughput (VHT) WLAN is one of IEEE 802.11 WLAN techniques, which is proposed to support a data processing rate of 1 Gbps or more. In particular, IEEE 802.11ac is developed as a standard for providing a very high throughput on the 5 GHz band, and IEEE 802.11ad is developed as a standard for providing a very high throughput on the 60 GHz band.
In systems based on the WLAN techniques, an access point (AP) manages stations by assigning a unique association ID (AID) to each of the stations whenever the station accesses the AP. During an operation between the AP and the station in the WLAN system, the AID, which is a unique number of the station, may be needed to be changed. When reassigning an AID to the station, the AP may reassign a new AID to the station, and the station may change an old AID to the reassigned new AID. In this case, when AIDs are reassigned to a plurality of stations, times at which old AIDs are changed to the reassigned new AIDs may be different for each station, resulting in a collision between the AIDs.